Patent Literature 1 describes an A/D converter. With this A/D converter, integral (or folding integral) A/D conversion is performed to an input analog signal, and cyclic A/D conversion is performed to a residual analog signal of the folding integral A/D conversion. In the folding integral A/D conversion, operation for A/D conversion is performed while repeating the sampling of the input signal and the integration of the sampled values, and a digital value is thereby obtained from an analog signal. With this method of A/D conversion, since the dynamic range can be expanded based on the folding operation while reducing the noise based on integration, it is possible to satisfy both low noise and dynamic range.